[dejswa]

Thank you for reading.

I have need to remove water and ethanol from a solution, being a sort of fermented potable mixture in order to later refine the solutes in their aqueous form for both quantitative and qualitative assessment.  The volume, would be less than a liter and could be done in incremental batches if more convenient.  I have looked at the various rotovap apparatus.  They are expensive and do more than I need as I want to discard the 'solvent' in this case. 

Have some labware experience from organic years ago and my inclination would be to just put a vacuum of some degree on the solution with some warming as tolerated.  The solutes may be sensitive to excess heat so I prefer to keep things less than 50C perhaps but I'm thinking I'll need some heat to help with vaporization and to at least prevent evaporative cooling, which would just slow things down.

I realize that the rotary action reduces bumping and increases surface area for vaporization.  However in the interest of economy, would there be any problem with just connecting a round bottom 24/40 flask, for ex to some sort of trap then to a (partial) vacuum line and have the thing in a semi temp controlled water bath?

I don't want to remove all the water but do want most of the EtOH gone, BTW

BTW, was wanting to upload an image from my computer.  Is that possible on this forum?  I see the picture icon but I think it is just for inserting a URL image.  It just uses the "[IMG]" tag.

Cheers,

DJ

[Arkcon]

What you've described is vacuum distillation, I did it in school,with no more vacuum than a faucet aspirator (I went to state school.)  Its probably not too hard to find something simple on Ebay, since you don't need to make multiple fraction collections.

[dejswa]

Thanks for the idea.  I watched a video on vacuum distillation.  I don't need the solvent so that simplifies things.  In the video, they used a closed, evacuated system with a heated flask and a super-cooled flask.  I have a medical vacuum pump that will do pump down to 100 millibar.  It's mainly meant for volume, not final vacuum rating.  I presume it can handle the vapors without damage since it is meant to deal with suctioning liquids with the use of a suction bucket (trap).

What do you think about just heating the one flask and applying the suction to the flask with the addition of some sort of trap off the flask?  No need for a collection flask.